Method of and apparatus for casting curved printing-plates and the like.



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BEST AVAILABLE COPY BEST AvAlLABLE COPY E. W. COOPER.

To all whom #may concern:

"UNITED STATES `PATENT OFFICE.

ELLIS W. COOPER, A0F BLOOMFIELD, NEW JERSEY, `ASSlGrNOR TO R. HOE AND C0., OF

NEW nYORK, N. Y., A CORPORATION OFl NEW YORK.

.METHOD OF AND APPARATUS FOR CASTING CURVED PRINTING-PLATES AND THE LIKE.

Specification of Letters Patent.

latented/J une 4, 1912.

Application filed October 22, 1910. Serial No. 588,449.l

Be it known that I, ELLIS W. COOPER, a-

-citi'zen of the United States, residing at Bloomfield, county of Essex, and State of New Jersey, haveinvented certa-in new and useful-Improvements in Methods of and Apparatus for Casting Curved Printing- Plates and the Like, fully described and rep'- resented in the following specification and the accompanying drawings, forming a part of the same.

This invention relates to certain improvements in methods ofand apparatus. for producing curved printing plates, and has been designed especially for use in casting.

the backing on curved elect-rotype-plates.

Some printing plates, particularly electrotype plates, are very thin and, before they can be used on the cylindersv of the printing machine for printing purposes, it is necessary that a backing be formed on them to enable them to withstand the printing operations. In producing curved electrotype plates ready for the printing operation, the present practice is to cast this backing on the electrotype plate in a flat mold, and when the mold has set, to bend the electrotype plate and it-s backing to curved or similar form. This method has many serious defects and disadvantages, especially on account of the unequal stretching of the metal during thevbending operation. This unequal stretching results in a lack of register, which is particularly objectionable in color printing, where4 a considerable number of `dierent impressions are made on the same forming the backing to ilow in over the faceof the electrotype, and, furthermore, on account of the backing being formed of different densities there resulted a distortion of the face of the eleetrotype plate or unequal pressure in printing.` n

The present invention has-for its object rto obviate the disadvantages referred to, and

4consists' in a novel method for casting the backingA on curved printing plates, particularly electrotype plates, by which the backing is cast so that it is uniformly distributed over the back of the plate and has a uniform density. These results are obtained by cast-ing the backing metal on the plate in arapidly rotating mold, so that the backing is deposited and distributed by the action of centrifugal force.

A vconvenient apparatus for carrying out the method and which forms part of my invent-ion, consists of a hollow drum having a removable cover to permit the insertion and withdrawal of the plate or plates to be backed, with means for rotating the drum. Suitable means, such as clamps, having surfaces which will not stop the flow of'the metal past thenr, are provided t-o hold the edges of the plate or plates and secure the same in position in the drum. The means for rotating the drum must be such that the speed of the drum will be suiiciently high to obtain the desired action of centrifugal the size of the drum, any speed securing such centrifugal force as to deposit and distribute the metal so that it has a uniform density being sufficient.` In carrying out the invention, a number of plates, covering substantially the entire inner surface ofthe drum, preferably are backed at one operation, the edges of the plates being secured The drum preferably is lirst run up to working speed, then a charge of the backing metal introduced, and the drum rotated until the backing Ihas set, A continuous backing is thus formed on the back of the plates, fthe clampspreventing metal from being deposited on the faceor printing surface of the plates. The'cover of the drum is'then removed, and the continuous platethus formed is cut out or otherwise separated into sections for the different plates Jand trimmed for use. :Of course, if desired, it is obvious that a plate or plates covering less than the whole of the inner surface of the drum may be operated on. In such case suitable filling blocks or plates may be employed, covering that portion of the inner surface of the drum notcovered by the plate or plates.

in the accompanying drawings, in. which- Figure 1 is 'a sideview, partly in section, of the drum and the means for supporting in place by the securing means, as clamps Such an apparatus of simple form is shown force, this speed depending somewhat upon vand driving it; lFig. 2 is an end view of a portion of the drum, showing the meansemployed for securing the cover of the drum 1n place; Fig. 3 is a view, partly inrsection, of

a. portion of the drum showlng the clamps employed for securing the plate or'.` 1n

therewith by a. feather 7. A removable open cover 8 is provided which covers one face of the drumand acts to hold the backing metal in the drum, while it is vbeing cast on the plate. The., means for securing this cover in position may be varied. As shown, the cover has a flange 9 adapted .to abut against a shoulder 10 formed on the drum. The flange 9 is held against this shoulder by screws A12 inlocking arms l'pivotally supported on studs 15, mounted in a flange 16 on the drum.

As before indicated, clamping means arel Vxrovided for securing the plate or plates 1n the drum'so that the metal will not work around onto the outer or print-ing surface of the plate. In the preferred construction,

these securing means are in the form of clamps 17, which overlap the meeting edges of two plates and extend the width of the plates and whichl preferably have' inclined surfaces, as indicated in Fig. 3, permitting the flow of metal past them. These clamps are held in clamping position and released` therefrom by bolts 18 passing through the walls of thedrum and act to hold the edges of the plates together and prevent metal -from Working between the edges of the plates and getting on the printlng surface thereof. As` before stated, a number of plates are preferably backed at one operation, a platea and a portion of t-wo other lates b, c, being shown in' Fig. 3 secured 1n the drum by these clamps 17. A charge of stereotype metal, which is to form ther backingof the plate, is introduced into the drum, preferably while the latter is rotating. To this end the cover of the drum is formed with a central opening,l as "shown in Fig. 1, and extending into the drum through this opening, is a supply pipe 19, arranged so that its deliveryV orifice is substantially central of the drum.

If desired', a heating means may be provided, such as a gas pipe 20, suitably located below the drum, to heat the drum so as to avoid anysudden chilling of the metal when introduced.

Preferably in this method of casting, the

plate/'or plates are bored or shaved out to uniform thickness while in the drum after the backing metal has set, it being obviously possible by any suitable tool or machine f( not shown) to rough .out thebacking formed throughout the entire surface of the drum.

f It will be understood that the apparatus employed for carrying out the method is not limited to that shown and' described, but that changes and variations may be made in the same without departing from the invention. i

What is claimed is 1. The .method of casting a backing on curved printing plates which consists in securing a plate in a mo'ldand introducing molten metal which is to form the backing of the plate into the interior of the mold, and rotating the mold at a speed suiicient to distribute the metal by centrifugal action against the inner surface of the plate until the metal has set.`

2 The method of casting'a backing on curvedprinting plates which consists inl securing a plate in a drum and introducing molten metal which is to forni the backing of the plate into the interior of the drum and rotating the drum at a speed suiicient to distribute the metal by' centrifugal action againstthe inner surface of the plate until the metal has set. l

3. The method ofmaking curved printing plates which consists in securing a plurality. of curved plates in a mold, introducing.

molten metal which is to form the backing -of the plates into the interior of the mold,

rotating the mold at a speed suiiicient'to distribute the metal by centrifugal action against the inner surface of the plates until the metal has set, and separating the continuous plate so formed lnto the diiferent 4. The method of making curved printing plates which consists in securing a plurality of curved plates in a drum, introducing molten metal which is to form the backing of the plates into the interior of the drum, rotating the drum at a speed suicient to distribute the metal by centrifugal action against the inner surface of the plates until the metal has set, and separating the continuous plate so formed mtothe different plates.A f

5. In an apparatus for making curved printing plates,the combination with a mold of means lfor removably securing a curved printing plate inthe mold, and means for rotating the mold to de osit a charge of molten metal introduced therein on the back of the plate. A

6. 1n an apparatus for making curved printing plates, Vthe combination with a mold pf means for-removably securing a plural- 1ty of curved printing plates in the mold, and means for rotating the mold to deposit a charge of molten metal introduced in the mold on the back of the plates.

7. In an apparatus for making curved printing plates, the combination with a mold and means for rotating it, of means for removably securing a plurality of curved printing plates in the mold, means for introducing molten metal in the mold, and means Afor heating the mold.

8. In an apparatus for making curved printing plates, the combination with a mold and means forv rotating it, of means for removably securing a plate in the mold so that its face is next the inner mold walls, means for introducing molten metal into the mold, and means for preventing the molten metal from coming into contact with the face of the plate.

9. In an apparatus for making curved printing plates, thev combination with a drum and means for rotating it, of means for introducing molten met-al `into the drum, and means for securing a. plate in the. drum so that the face of the plate is next to the inner wall thereof and for preventing molten metal fromcoming into contact with the face of the plate.

10,. In an apparatus for making curved printing plates, the combination of a drum having a cover, means for rotating'the drum, means for introducing molten metal into the drum, means for clamping a plate in the drum Softhat its face is next to the inner Wall thereof and for preventing the molten metal from coming' into contact with the face of the plate, and means for removably securing the cover to the drum.

11. In an apparatus for making curved printing plates, the combination wit-l1 a mold and means for rotating it, of clamps for securing plates in the-mold so that metal introduced in the mold will not come in contact with the face of the plate.

l2. In an apparatus for making curved printing plates, the combination with a drum and means for rotating it, of clamps overlapping the meeting edges of two plates and extending the width of the plates for securing the plates in the drum and preventing metal introduced into the drum from coming in contact with the faces of the plates.

13. In an apparatus for making curved printing plates, the combination with a drum and means for rotating it, of clamps having curved surfaces overlapping the meeting edges of two plates and extending the width thereof for securing the plates in the drum, and preventing metal introduced into the drum from coming in cont-act with the faces of the plates.

In testimony whereof, I have hereunto set my hand, in the presence of two subscribing witnesses.

ELLIS WV. COOPER.

Witnesses F. W. H. CRANE, RICHARD KELLY. 

